The Prickly Pear cacti open their blossoms during the day, they are open the most from noon to 4:00 PM. This is the plant I photographed in the evening a few days ago, the flowers were closed during that time.
Interesting and beautiful. Most of the prickly pear in our area are yellow. On the way to Wichita Falls a couple of year ago, I saw one, and made Roland stop, that had about 4 different colors of flowers on it. So they do come in all colors. I love their blossoms.